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Thread: Need advice for 3800 series 2 turbo

  1. #1
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    Need advice for 3800 series 2 turbo

    Ive been researching and reading up on hp tuners for about a year now. Even when i didnt own hp tuners, i downloaded the software and some 3800 tunes, to look at while reading and watching videos. Trying to get the hang of it. So that way when i finally got to install the PnP heads with #136 springs, bigger Intake and Exhaust valves, Bigger Cam ( ZZP'S stg 4 turbo cam ), ls7 lifters, on top of the turbo kit i bought from Cartuning ( which came with a tuned pcm, ls1 MAF, and lucas 42.5 lbs injectors ). So i could just get to tuning it.
    But it hasnt been quite that easy. I cant find any tutorials for the 3800 on setting up the idle. The ones i did find are either non existent now ( write up on turbov6 ) , only start the write up if your car can already idle, or if it is about idling then there are tabs and tables i dont have on my pcm. And i dont want to skip over things or make the wrong adjustments and mess up my car.

    So from the research ive done you want to adjust the base target idle ( or in my case its just called BASE ) in the idle tab. Then goto the idle airflow and adjust it. But now this is where my problem starts cause i dont have that table in my idle tab. So i dont know what i have to adjust next for the idle air flow. If yall could give me some knowledge, I would greatly appreciate the help.

  2. #2
    Tuning Addict 5FDP's Avatar
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    3800 computers don't have that, so what you see is what you get pretty much.

    Set the idle at 900-1000 for starters. Then see if it will run. Watch your wideband to see how fueling is doing. If it's lean you will need to add fuel to the MAF curve to make it happy and if it's rich, remove a little bit of fuel. Next you have the timing, playing with timing in the idle area's is the other factor to helping it run good there.

    Once it can idle on it's own, you'll just need to start tuning with your wideband to make fueling correct everywhere throughout the MAF curve.
    2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.

    If you don't post your tune and logs when you have questions you aren't helping yourself.

  3. #3
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    I set the idle to 950rpm. To adjust the maf curve i would goto maf calibration - Airflow vs. FREQ ? And to adjust the timing i goto Spark, Advanced and then Base Low Octane ?

  4. #4
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    Yes, the MAF airflow vs freq is how you'd adjust the MAF.

    Adding to the curve adds more fuel and lowering the values removes fuel. How much you need to adjust it will depend on what your wideband o2 sensor is telling you.

    The high octane table is what it will use 99% of the time. The low octane table is there if the engine has knock retard and needs to pull timing away. That is why the timing is less than the high table. The computer with use a knock learn factor to interpolate the timing between the two tables when knock is present and then revert back to only the high table when the KLR returns to normal.
    2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.

    If you don't post your tune and logs when you have questions you aren't helping yourself.

  5. #5
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    I will give a try. Thanks

  6. #6
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    After adding 1 gram to the maf curve in the 1500 - 3875hz section, 2 degrees of timing through the 0.08 - 0.28 grams and 400 - 1,200 rpm range in the hi octane table, the car is now able to start and hold idle.

    While researching i came across a write up on how to connect your WB to the egr if you dont have the pro version. . The write up is for an older version of hp tuners. How would i do this in the new version. I dont see the function part to put the equations in

    https://www.3800pro.com/forum/pcms-t...#/topics/31724
    Last edited by 1FasImp; 02-22-2020 at 07:05 AM.

  7. #7
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    I found a how to on youtube for the wb and erg for a 5.3 Silverado.
    https://youtu.be/NDyiq3A5MIc

    Would this work on the 3800 pcm?

  8. #8
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    The video above works on the 3800. I was able to get my AEM uego 30-0300 wb to log in vcm scanner through the Egr signal wire. I just have to play with a number in the equation to get it to read what the WB is saying. I got It very close, i believe. The WB and Log change faster then i can look lol.

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    rather than hooking it up to egr use the 5v reference pin which on your ecu should be on the clear connector pin 27 if i recall correctly. find a pinout of your ecu to reference. then on your next log session, add ac pressure sensor voltage which is where you ran that wire. dont use the serial signal from the sensor though, just the 5v reference wire. and with the instructions that came with the wideband you can use the voltage output to find afr. its a bit of a pain but it works

  10. #10
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    Is there a write up on it?

  11. #11
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    Probably somewhere but it?s as simple as that, all you do is run the 5v signal from the o2 sensor to the ac pressure 5v pin on the ecu as long as you don?t have ac.. and add the ac pressure voltage to your data logging and the 0-5v scale should be on the website of whatever brand wideband your using to convert voltage to afr. That way you watch the gauge while driving then if you see a spot that needs altering go back in the log afterward and convert the voltage to find exactly where it was

  12. #12
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    Any equation need like with the egr?


    Edit ****

    I found this video tutorial
    https://youtu.be/Ru_2M2uGSKs
    Last edited by 1FasImp; 03-03-2020 at 02:31 PM.

  13. #13
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    I am still trying to get this math equation correct for the egr to jive with WB. I took a vid with the wb and scanner while logging for an idle tune, so I could pause the video and see how much it was off by. I found its like +/- .20 or so off. So if my WB is reading a 14.70, it'll read like a 14.54 in the scanner. I tried to do my own math with my wb scaling table but it was way off. I posted a couple of screenshots of the math and a pic of my WB scaling output table. Could yall help me out with it

  14. #14
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    After more researching and using lot of different word play in google, I came across a thread for the AEM WB ( 30-0300) EGR Formula for the standard interface on an l67.

    https://forum.hptuners.com/showthrea...dard-interface)

    After reading through it, they were having the same issues with the wb and scanner being off with the more popular formulas. They then pointed out that the manual had the formula for AFR and Lambda. So I look at my manual and..... Be hold theres the freaking Formula

    AFR = (2.3750*volts)+7.3125
    Lambda = (0.1621*volts)+0.4990

    So I type in (2.3750*[2811.10])+7.3125 for the Expressions, and went and tested it. I took three pics to compare the WB and scanner. It was off by .04
    For the Error expressions I used this formula 100*((2.3750*[2811.10])+7.3125-[50121])/[50121]) I honestly don't know if its correct.


    Can yall look over my tune and idle log to make sure im headed in the right direction

  15. #15
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    I did some maf adjusting to the tune with the log in my last post. I also did a log after writing the changes to the pcm. Any insight would be greatly appreciated. I attached the tune with the maf changes and the log with the changes.

  16. #16
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    If you have the wideband working and the error graph working, that is good.

    I want to assume the data you are gathering for the wideband error are with the fuel trims shut off. Otherwise you'd be getting data from a computer that is auto trimming fuel with STFT and LTFT active and you don't want that. Also closed loop has to be disabled.
    2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.

    If you don't post your tune and logs when you have questions you aren't helping yourself.

  17. #17
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    I believe the afr error is correct. I idont know if i typed the experssion formula in correctly or not. To shut off full trims you mean by resetting them? Closed loop wasnt enabled, to do that do i raise the temp to something that the car wont hit?

  18. #18
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    Yes, you'd raise the coolant temp enable and click reset trims and disable fuel trim learn I think in the VCM scanner prior to logging data.
    2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.

    If you don't post your tune and logs when you have questions you aren't helping yourself.

  19. #19
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    Awesome. Ill do that. I was reseting fuel trims but not disabling the fuel trim learn. What about any afr tables, would i need to change any of them?

  20. #20
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    No. The error graph is always telling you how far off the actual fueling is compared to the commanded. It doesn't matter if it's at stoich or if you enter power enrichment, it's just telling you the error between the two.
    2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.

    If you don't post your tune and logs when you have questions you aren't helping yourself.